1. Field of the Invention
The present invention relates to sorting handlers for testing electric characteristics of a device, such as a semiconductor device of which production is finished, and more particularly, to a sorting handler for a burn-in tester for carrying out a burn-in test that is a heat resistance test carried out before shipment of the device to minimize occurrence of defect at the device caused by heat generated during use of the device applied to a product.
2. Background of the Related Art
In general, devices, such as semiconductor devices, are assured of product reliability by testing various electric performances of finished devices at a tester, and only shipping good products as a result of the test.
For minimizing occurrence of the defect due to heat under an actual environment of use, the burn-in test is carried out as one of device tests. The sorting handler for a burn-in tester is an apparatus for carrying out a series of works of unloading the device tested at the burn-in tester from a test board, sorting at shipment trays according to a result of the test, and loading new devices to be tested on the test board, automatically.
The Korean Laid Open Patent No. 2000-0065749 (Published on Nov. 15, 2000) which is applied, and registered by the applicant discloses a sorting handler for a burn-in tester which enables size and system of the apparatus compact, makes exchange of trays at a sorting part easier, and shortens a test time period.
FIG. 1 illustrates a diagram of the sorting handler for a burn-in tester schematically, provided with a loader part 3 in one side part of a body 1 having trays mounted thereon for receiving devices to be tested newly, an unloader part 4 opposite to the loader part 3 having trays mounted thereon for receiving good devices as a result of the burn-in test, and a sorting part 5 between the loader part 3 and a front part of the unloader part 4 having trays mounted thereon for receiving defective, or re-test devices as the result of the burn-in test.
There are a rack 2 on one side of the body 1 for supplying burn-in boards ‘B’ having burn-in tested devices loaded thereon, and an X-Y-θ table under the body 1 for drawing the burn-in board ‘B’ from the rack 2, introducing the burn-in board ‘B’ to an inner side of the body 1, returning the burn-in board ‘B’ to an original position of the rack 2, and moving the burn-in board in an X or a Y direction by one step at a working position.
There are a DC testing part 8 at a side of the loader part 3, an unloading buffer 10 at one side of the unloader part 4, and a working space between the DC testing part 8 and the unloading buffer 10 where the burn-in board ‘B’ is positioned.
There is an X-axis main shaft 6 crossing the body 1 over the DC testing part 8, the burn-in board ‘B’, and the unloading buffer 20, having a loading picker 11 for transferring the devices from the loader part 3 to the DC testing part 8, an insert picker 12 and a remove picker 13 for transferring the devices from the DC testing part 8 to the burn-in board ‘B’, and from the burn-in board ‘B’ to the unloading buffer 10, and an unloading picker 14 for transferring the devices from the unloading buffer 10 to the unloader part 4. The insert picker 12 and the remove picker 13 are coupled to a slider (not shown) moving along the X-axis main shaft 6, to moving along the X-axis main shaft 6 together.
There is a sorting picker 15 arranged over the sorting part 5 to move along sorting X-, and Y-axis shafts 7 for transferring defective devices from the DC testing part 8 and the unloading buffer 10 to the sorting part 5.
There is a tray transfer 18 arranged in a rear part of the loader part 3 and the unloader part 4 to move along a tray transfer X-axis shaft 19 for transferring empty trays having all devices loaded on the loader part 3 to the unloader part 4.
The operation of the related art sorting handler for a burn-in tester will be described.
When a worker loads burn-in tested burn-in boards on the rack, and puts the handler into operation, the X-Y-θ table 20 moves toward the rack 2, draws one of the burn-in boards ‘B’ from the rack 2, moves to the central working space of the body 1, and turns the burn-in board at 90°.
Then, the tray ‘T’ at the loader part 3 moves backward to a position under the X-axis main shaft 6, and the loading picker 11 holds the device at the loader part 3, and moves to the DC testing part 8. A simple DC test is carried out at the DC testing part 8, when the loading picker 11 moves to the loader part 3 again, and holds the next device for transferring to the DC testing part 8.
When the DC test is finished at the DC testing part 8, both the insert picker 12 and the remove picker 13 respectively move to positions over the DC testing part 8 and the burn-in boards ‘B’ at the same time. Then, the insert picker 12 holds the device at the DC test part 8, and the remove picker 13 holds the burn-in tested device on the burn-in board ‘B’ of the remove picker 13.
Both the insert picker 12 and the remove picker 13 move to left when the drawing is seen from above, load the devices on the burn-in board ‘B’ and the unloading buffer 10, and move to the DC testing part 8 and the burn-in board ‘B’, again, respectively.
Then, the unloading picker 14 transfers the burn-in tested good devices on the unloading buffer 10 to the tray ‘T’ on the unloader part 4. If there is any defective device on the unloading buffer 10, the sorting picker 15 moves to the unloading buffer 10 along the sorting X-, and Y-axis shafts 7, holds the defective device, and loads on the tray ‘T’ on the sorting part 5.
If all the burn-in tested devices are removed from the burn-in board ‘B’, and new devices are stuffed thereon, the X-Y-θ table 20 transfers the burn-in board ‘B’ to an original position of the rack 2.
In the meantime, the related art sorting handler for a burn-in tester has a drawback in that, after the insert picker 12 and the remove picker 13 transfer the devices from the DC testing part 8 and the burn-in board ‘B’ to the burn-in board and the unloading buffer 10, the insert picker 12 and the remove picker 13 return to the positions of the DC testing part 8 and the burn-in board ‘B’ again, with empty handed, i.e., without any real work, that makes both working efficiency, and test productivity per unit time period (UPH=units per hour) poor.
The unidirectional work flow of the related art sorting handler for a burn-in tester, in which only device loading is made in one side part of the handler body, and only device unloading is made in the other side part of the handler body, results in a poor work efficiency.
To cope with this drawback, the applicant discloses a sorting handler for a burn-in tester in the Korean Laid Open Patent No. 2000-0067665 (Laid Open on Nov. 25, 2000) suggesting two DC testing parts and the buffers arranged in symmetry with reference to burn-in board to progress device loading/unloading in both side parts of the body simultaneously, for reducing a testing time period, and improving working efficiency.
However, the foregoing sorting handler for a burn-in tester has a drawback in that the working time period can be reduced and the working efficiency can be improved only when one kind of work is selected, and carried out at the both side parts simultaneously during the device loading and unloading.
In other words, the working efficiency can be improved by using the both side parts as the loader parts, or the unloader parts when the sorting handler for a burn-in tester carries out loading work only in which a new device is loaded on the burn-in board, or unloading work only in which the device is transferred from the burn-in board to the tray.
However, since it is impossible that the pickers pick up a device from the burn-in board and putting a new device to be tested on the space at the same time while the pickers move along the X-axis main shaft over both side parts of the burn-in board, such a work can not but be unidirectional, that results in a poor testing work efficiency.